Proportion of CD34⁺CD38⁻CD123⁺ Leukemia Stem Cells at Diagnosis Varies in ELN Risk Groups and an Emerging Novel Marker for Prognosticating the Intermediate Risk patients of Acute Myeloid Leukemia: A Prospective Study

The proportion of CD34 ⁺ CD38⁻CD123⁺ leukemia stem cells (LSCs) at diagnosis of Acute Myeloid Leukemia (AML) correlated with induction remission (IR), relapse free survival and overall survival in few studies. Prospectively bone marrows of AML patients were immunophenotyped for CD34 ⁺ CD38⁻ CD123 ⁺LSCs at baseline using sequential gating, relevant clinical and laboratory data collected and clinical outcomes were studied.The patients (n = 47) were risk stratified as favorable risk, intermediate risk and adverse risk. The percent of LSCs at baseline in favorable risk group (mean = 13.06%) was significantly less than the adverse (mean = 34.8%, p = 0.027) and the intermediate risk group (mean = 53.2%, p = 0.001). On further analysis, 12 patients attaining IR in intermediate risk group had significantly less LSCs than 15 in non-IR group (mean = 21.18%; range 3–85.6% vs mean = 73.85%; range 12.1–97.9%, p = 0.0002). Of all 47 patients, the proportion of LSCs at baseline was significantly less in those achieving IR (p = 0.024) and correlated with time to response (TTR) (r_s= 0.432). Thus to conclude, the proportion of CD34 ⁺ CD38 ⁻CD123⁺ LSCs at diagnosis is less in the favorable than the intermediate and adverse risk groups and is  an emerging novel marker for predicting remission in the prognostically diverse intermediate risk group.